openssl_utils.h

/*
 * Copyright 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef SYSTEM_KEYMASTER_OPENSSL_UTILS_H_
#define SYSTEM_KEYMASTER_OPENSSL_UTILS_H_

#include <openssl/bn.h>
#include <openssl/ec.h>
#include <openssl/engine.h>
#include <openssl/evp.h>
#include <openssl/rsa.h>
#include <openssl/x509.h>

#include <keymaster/UniquePtr.h>

#include <hardware/keymaster_defs.h>

namespace keymaster {

struct KeymasterKeyBlob;

class EvpMdCtxCleaner {
  public:
    explicit EvpMdCtxCleaner(EVP_MD_CTX* ctx) : ctx_(ctx) {}
    ~EvpMdCtxCleaner() { EVP_MD_CTX_cleanup(ctx_); }

  private:
    EVP_MD_CTX* ctx_;
};

template <typename T, void (*FreeFunc)(T*)> struct OpenSslObjectDeleter {
    void operator()(T* p) { FreeFunc(p); }
};

#define DEFINE_OPENSSL_OBJECT_POINTER(name)                                                        \
    typedef OpenSslObjectDeleter<name, name##_free> name##_Delete;                                 \
    typedef UniquePtr<name, name##_Delete> name##_Ptr;

DEFINE_OPENSSL_OBJECT_POINTER(ASN1_BIT_STRING)
DEFINE_OPENSSL_OBJECT_POINTER(ASN1_INTEGER)
DEFINE_OPENSSL_OBJECT_POINTER(ASN1_OBJECT)
DEFINE_OPENSSL_OBJECT_POINTER(ASN1_OCTET_STRING)
DEFINE_OPENSSL_OBJECT_POINTER(ASN1_TIME)
DEFINE_OPENSSL_OBJECT_POINTER(BN_CTX)
DEFINE_OPENSSL_OBJECT_POINTER(EC_GROUP)
DEFINE_OPENSSL_OBJECT_POINTER(EC_KEY)
DEFINE_OPENSSL_OBJECT_POINTER(EC_POINT)
DEFINE_OPENSSL_OBJECT_POINTER(ENGINE)
DEFINE_OPENSSL_OBJECT_POINTER(EVP_PKEY)
DEFINE_OPENSSL_OBJECT_POINTER(PKCS8_PRIV_KEY_INFO)
DEFINE_OPENSSL_OBJECT_POINTER(RSA)
DEFINE_OPENSSL_OBJECT_POINTER(X509)
DEFINE_OPENSSL_OBJECT_POINTER(X509_EXTENSION)
DEFINE_OPENSSL_OBJECT_POINTER(X509_NAME)

typedef OpenSslObjectDeleter<BIGNUM, BN_free> BIGNUM_Delete;
typedef UniquePtr<BIGNUM, BIGNUM_Delete> BIGNUM_Ptr;

keymaster_error_t ec_get_group_size(const EC_GROUP* group, size_t* key_size_bits);
EC_GROUP* ec_get_group(keymaster_ec_curve_t curve);

/**
 * Many OpenSSL APIs take ownership of an argument on success but don't free the argument on
 * failure. This means we need to tell our scoped pointers when we've transferred ownership, without
 * triggering a warning by not using the result of release().
 */
template <typename T, typename Delete_T>
inline void release_because_ownership_transferred(UniquePtr<T, Delete_T>& p) {
    T* val __attribute__((unused)) = p.release();
}

keymaster_error_t convert_pkcs8_blob_to_evp(const uint8_t* key_data, size_t key_length,
                                            keymaster_algorithm_t expected_algorithm,
                                            UniquePtr<EVP_PKEY, EVP_PKEY_Delete>* pkey);

keymaster_error_t KeyMaterialToEvpKey(keymaster_key_format_t key_format,
                                      const KeymasterKeyBlob& key_material,
                                      keymaster_algorithm_t expected_algorithm,
                                      UniquePtr<EVP_PKEY, EVP_PKEY_Delete>* evp_pkey);

keymaster_error_t EvpKeyToKeyMaterial(const EVP_PKEY* evp_pkey, KeymasterKeyBlob* key_blob);

size_t ec_group_size_bits(EC_KEY* ec_key);

}  // namespace keymaster

#endif  // SYSTEM_KEYMASTER_OPENSSL_UTILS_H_